Hi Graham,
I tried to reply to you pm address, but your provider keeps bugging
me with failed deliveries and error messages like
"We have limits for how many messages can be sent per hour and per
day."
Nnnngrrrrr...
My excuse to the group for hijacking the reflector for the following
response, which should have been sent directly.
You asked:
>>>
Can you advise on settings
I need to measure the drift of
TX , using my RA1778 (high stab master osc) / M-Delt 4 96K
sound card , to produce audio frequency of 1500 Hz
Ideal would be to show 1 HZ
or 2 Hz full screen ( 1499 > 1501) or ( 1499.5
> 1500.5)
If I zoom in on the frequency
, the display becomes very ''block like''
The measurements need to be
60 seconds apart , to give a drift from cold plot
Q Is it possible to make such
measurements ?
<<<
If the measurements may only be 60 Hz apart, the normal FFT
will not give the ultimate resolution (thus the screen will look
block like when zooming in). With a measurement time of 60 seconds,
the best you can get is something around 1/60s = 16.6 mHz effective
resolution.
There are two alternatives:
A - use the experimental "time/frequency reassigned spectrogram" (it
gives a readout resolution which is MUCH better than the FFT
resolution dictated by the FFT length). Details about this rarely
used function are here:
http://www.qsl.net/dl4yhf/speclab/ra_spectrogram.htm
B - use the 'phase-and-amplitude' monitor. If only produces numeric
output (no waterfall-like display), but you could plot the
frequencies in the 'watch window'. The phase/amplitude monitor
function can also measure frequencies. Details are here:
http://www.qsl.net/dl4yhf/speclab/phase_amplitude_monitor.htm
For a start, the reassigned spectrogram may be the easier
alternative. There are a few preconfigured settings which you can
recall through the 'Quick Settings' menu.
Hope this helps,
73, Wolf .
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